SPACE.com -- Experts meet at American Institute Aeronautics and Astronautics X-vehicle symposium


	Experts meet at American Institute Aeronautics and Astronautics X-vehicle symposium By Glen Golightly Houston Bureau Chief posted: 09:48 am ET 18 June 2000

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WASHINGTON The essence of experimental craft might be summed up in a Zen riddle: in failure, you will find success.

Designing, flying and using the technology from X-craft is a difficult road indeed, according to a whos-who of experimental vehicle pioneers past, present and future. They met recently in Washington for the American Institute Aeronautics and Astronautics X-vehicle symposium.

The X-38 is one in a long line of experimental aircraft designs. Watch the video of one of the vehicle's test drops.

From Chuck Yeagers breaking the sound barrier aboard the X 1 in 1947, to the hypersonic X 15 in the 1960s that developed space-shuttle technology, to the bathtub-like lifting bodies of the 1960s, to recalcitrant composite fuel tanks in todays X 33 only the hardy and crafty will succeed or fail.

The X 38 on a test flight

Its not just careers or funding on the line pilots risked and sometimes lost their lives in these edge-dancing craft. Test pilot Glenn Edwards lost his life in the crash of an early flying-wing bomber prototype and Mike Adams died after his X 15 crashed following a high-altitude flight.

At a Glance: Current Space-related X-craft

Air-breathing hypersonic vehicles under development, like the Hyper-X, should fly between Mach 7 and 10.

"Theyre about pioneering, about taking risks," said Lockheed Martins Michael Francis, who managed the X 31 program. "Thats the nature of the beast."

Success can come in strange ways with experimental craft. Building a large number of planes or long-term usage arent indicators of success. An experimental craft exists only to do two things, says the Air Forces chief historian Richard Hallion.

"Theyre simply research tools and technology demonstrators," Hallion said.

He pointed out that data from the X 1 series, like those flown by Yeager, proved useful in combat over the frozen fields of Korea when U.S. F 86 Sabres wrested air supremacy from Soviet MiG 15s. The Sabres had the edge because they had a full-motion horizontal stabilizer that the MiG didnt, allowing the Sabres a huge advantage in maneuvering in dogfights.

Gathering of the "Graybeards"

The "Graybeards" or old timers who attended the X-vehicle symposium had lived and worked in what some consider the golden age of the X-craft from the 1950s to 1970s. Oftentimes these engineers are brought in to consult so that younger and less experienced engineers dont repeat the same mistakes from years ago.

Johnny Armstrong, director of the Access to Space office at Edwards Air Force Base, played a key role in the X 15 program that provided reams of data later used in the space shuttle and high-speed aircraft.

The X 15 in flight

He reminded the group that the X 15 pioneered more than hypersonic flight -- flying more than five times the speed of sound. Among its contributions were the introduction of simulators to train for a mission and the use of a "mission-control" scheme to gather data and assist the pilot during flight. The U.S. human space program picked up those ideas and still uses them today.

He laments that things have changed in experimental programs today. Armstrong said the camaraderie and teamwork just isnt the same.

"Theres not a human in the cockpit," he says of current programs. "When theres a pilot, it invigorates the team and motivates them."

The X 15 landing

Programs are more formal, complicated and risk-averse these days, but there was a time when you could fund a project for a shoestring.

Dale Reed, a semi-retired engineer at Dryden, began informal research into lifting-body shapes in the early 1960s. Funding came from the center directors discretionary funds. And he found personnel from the project where he could.

Though the lifting bodies looked promising for going to space and back, NASA stayed with the capsule design through the Gemini and Apollo programs. Had a lifting body been used, astronauts would have landed on a conventional runway rather than splashing down in the ocean.

Artist's representation of the X 43 in flight

Today, the space agency has reconsidered and the X 38 prototype for the International Space Station's Crew Return Vehicle (CRV) draws on research conducted on lifting bodies.

"There was just a lot of skepticism," Reed said, happy that his research finally paid off. "It just took time."

The X 33 and VentureStar also take their wedge shape from the 1960s and 1970s lifting-body research.

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